The present invention relates to a method of producing a dielectric film, and particularly to a method of producing a dielectric film having a low dielectric constant used as an interlayer insulating film of a semiconductor device.
With progress of the finer design rule, there has been appointed a problem on a delay of an interlayer capacity due to an interlayer insulating film. To cope with such a problem, there is increasing the necessity to reduce a dielectric constant of an interlayer insulating film. A method for reducing a dielectric constant of an interlayer insulating film is disclosed in Japanese Patent Laid-open No. Hei 05-283542, wherein voids are positively formed in an interlayer insulating film to thereby reduce an effective dielectric constant. This method involves coating a surface of a substrate with a coating material in which a main material for forming an interlayer insulating film is mixed with fine particles of a material (aluminum, in this case) different from the main material, solidifying the coating film, and selectively etching the fine particles using an etchant allowed not to etch the main material but to etch the fine particles so as to form voids, thereby forming an interlayer insulating film in which the voids are dispersed throughout.
The above method of forming an interlayer insulating film, however, has a problem that metal fine particles remaining in the interlayer insulating film may cause short-circuit between interconnections, resulting in the reduced yield.